• Journal of the Korean Wood Science and Technology
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• v.9 no.2
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• pp.1-30
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• 1981

To investigate the formation of the chromophoric structures taking place during the alkaline pulping vanillyl alcohol [${\alpha}-^{13}C$] guaiacylglycerol-${\beta}$-aryl ether [${\alpha}-^{13}C$ or ${\gamma}-^{13}C$] and phenylcoumarn [${\alpha}-^{13}C$] units as model lignins were treated with 1N sodium hydroxide at 165$^{\circ}C$ for 1.5-3 hours. From the chemical structures of the isolated products and $^{13}C$-NMR Spectra of the reaction mixtures, the main conclusion is as follows; 1) Condensation products of II-1-5 were identified from the reaction mixture of vanillyl alcohol treated with alkali and theses compounds afforded the quinonmethide structure(Fig. 3-7) by air oxidation. 2) Treatment of guaiacylglycerol-${\beta}$-aryl ether unit gave ${\varphi}$-aryl-${\beta}$-aroxy quinone structures (IV-15, IV-16), diguaiacyl-1, 4-penta-diene ${\beta}$, ${\beta}$'-diaroxyl distyrene methane unit, ${\beta}$-aroxy distyrene methane. These distyrene methanes of the compounds are transformed by air oxidation into the corresponding o-quinonemethide units (V-8, V-9). 3) On the treatment of phenylcoumaran, the stilbene derivative was formed in quantitative yield and dimerized(VI-11) in preference to oxidation to the corresponding extended quinone structures. The chromophoric structures taken place during the alkaline treatment of the model lignins are thought to be some important types in alkaline pulping on the basis of the reaction mechanism in this experiment.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.230-241
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• 2010

The purpose of this study was to seek the optimum condition for effective separation of the chemical constituents of wood biomass by means of hydrolysis of acetone solution in presence of acid salt as a catalyst. Out of diverse acid salts the catalytic effect of aluminum sulfate ($Al_2(SO_4)_3$) was the most excellent during the hydrolysis of wood biomass in the acetone solution and the optimum concentration was 0.01 M (6.3 wt%). In the condition of mixture ratio of acetone and water to 9 : 1 as well as optimum concentration of aluminum sulfate two wood biomass species, oak wood (Quercus mongolica Fischer) and Pine wood (Pinus densiflora Sieb. et Zucc.), was hydrolyzed for 45 minutes at $200^{\circ}C$ and the degree of hydrolysis was determined to 92.7% and 92.4%, respectively. Extending the reaction time to 60 minutes in the mixture ratio of acetone and water to 8 : 2 the degree of hydrolysis of oak wood was also ca. 92.7%. In the case of Pinus, however, the similar hydrolysis ratio was obtained at $210^{\circ}C$. As the temperature and hydrolysis time increased, the quantitative amount of lignin recovered from the hydrolysate clearly increased, whereas the total amount of carbohydrates in the hydrolysate decreased rapidly. Considering the recoverable amount of lignin and carbohydrate in the hydrolysate, the best condition for the hydrolysis of wood biomasses were confirmed to the mixture ratio of acetone and water to 8 : 2, the concentration of aluminum sulfate of 6.3 wt%, hydrolysis temperature of $190^{\circ}C$ for 60 minutes. In this condition the total amounts of carbohydrate in the hydrolysates of oak wood and pine wood were estimated to 47.6% and 51.4%, respectively. The amount of lignin recovered from the hydrolysates were ca. 18.2% for oak wood and 13.7% for pine wood.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.42-51
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• 2013

In this study, oil palm biomass such as empty fruit bunch (EFB) and palm kernel shell (PKS) was used as raw materials for making pellets. Hardwood sawdusts were also mixed with EFB and PKS for making pellets. For improving a bad forming behavior in a pelletizer, 1 to 3 per cent of corn starch based on oven-dried weight biomass was added. The starch contributed to the decrease of dust generation in addition to the improvement of forming capability during pellet forming. Heating values of every pellets made of EFB and PKS were higher than 4,300 kcal/kg for the first grade pellet, irrespective of addition of sawdusts. However, the pellets made of EFB and PKS had ash contents over 3 per cent, which made it impossible to be applied for home use. Instead, they could be applied for industrial use. For studying their combustion characteristics, the pellets from the mixtures of EFB, PKS and sawdusts were analyzed using thermal gravimetric analyzer (TGA). From the TGA results, thermal decomposition of EFB and PKS occurred following three including endothermic reaction and dehydration, devolatilization of the major chemical components, and finally combustion of residual lignin and char.

• Journal of the Korean Wood Science and Technology
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• v.38 no.2
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• pp.149-158
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• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.27-32
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• 1995

To understand whether ligninolytic enzyme catalyze polymerization or depolymerization of the high molecular weight (HMW) lignin, the action of laccase and Mn-peroxidase (MnP) towards commercial ligninsulfonates (LS) was examined in various conditions of pH and cosubstrates. Polymerization occurred when LS was incubated with laccase at pH 6.0. In contrast, the high molecular weight portions were significant1y reduced at pH 4.5, especially when glucose was added. When LS was treated with MnP at pH 4.5, compounds of low molecular weight were produced. In particular, when cellobiose was added to Mn-P reaction mixture, the breakdown of LS was observed. In conclusion, degradation of LS by laccase and MnP occurred primarily at pH 4.5 where-as polymerization of LS was dominant at pH 6.0. Color index, however, was not greatly changed in the degradation mixtures of LS.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.52-57
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• 2008

In this study, the effects of carbonization temperature on the physico-chemical properties of porous wood charcoal are studied by FT-IR and Raman spectroscopies. IR studies showed that cellulose and hemicellulose are mostly decomposed in the precarbonization stage at $500^{\circ}C$, while the decomposition reaction of relatively more stable lignin lasts up to $700^{\circ}C$. Above $900^{\circ}C$, the peak at $1575cm^{-1}$ disappears and a new peak at $1630cm^{-1}$, which seems to be related to the new carbon deposit phase, is evolved. The results of Raman studies, which show the red-shift of D-band and the increase in the relative intensity of D- to G-band, indicate that the size of the crystalline becomes smaller with increasing the carbonization temperature.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.27-33
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• 1994

This study was conducted to determine the nutritional value of native oriental white oak(Quercus aliena Blume) browse by Korean native goats. Oak browse were mixed with grass hay(orchardgrass 60% and red clover 40%), varing in oak browse content. Diets included 30% oak browse and 70% grass hay, 60% oak browse and 40 % grass hay, and a 100% grass hay(contro1). Oak browse diets were higher in NDF, ADF, lignin, and tannin contents, but lower in CP content than the control diet with increased oak browse levels. Gross energy levels showed no difference between the control and oak browse diets. Dry matter intake was the lowest on diet containing oak browse 60%. Digestibility for DM, cellular constituents, NDF, and ADF showed lower for oak browse diets compared to control diet(P<0.05). Oak browse diets furnished significantly lower dietary N than &d the control diet. Fecal N losses generally increased with higher levels of oak browse levels(P<0.05). Apparently digested N and retained N were lower in oak browse diets than in control diet. The higher retained N was obtained in control diet than in oak browse diets. DE and ME declined linearly as oak browse levels increased when compared to control diet(P

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.440-444
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• 2012

In this work, a semi-carbonized wood chip (SC-WC) was prepared by heat-treatment at low carbonization temperature. The pyrolysis characterization and heating value of the SC-WC at different heat-treatment temperature were evaluated. The pyrolysis characterization and heating value of the SC-WC were determined using thermal gravimetric analyzer (TGA) in $N_{2}$ atmosphere and calorimeter, respectively. From the TGA results, the thermal decomposition reaction of the SC-WC treated at by low temperature was similar to pure wood chip and the reaction was most actively occurred in the range of $200^{\circ}C$ to $400^{\circ}C$, whereas the initial thermal decomposition temperature of the SC-WC increased with the increasing heat-treatment temperature. In addition, the heating value of the SC-WC showed a similar trend as to the decamposition temperature behavior. This is probably attributed to increased carbon content of SC-WC by the localized carbonization of the wood chip which consisted of cellulose, hemi-cellulose, and lignin.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.397-405
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• 2009

In this study, we investigated the potential of producing bioethanol from Liriodendron tulipifera by using oxalic acid pretreatment. Amounts of fermentable sugars, mostly xylose and glucose, in the liquid fraction (hydrolysate) was $40.22g/{\ell}$ after the biomass was pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$. Production amounts of ethanol was $8.6g/{\ell}$ from the 72 hours of simultaneous saccharification and fermentation (SSF) on solid fraction of the pretreated sample. At the same condition, when the reaction time increased to 40 minutes, $32.66g/{\ell}$ of fermentable sugars in the hydrolysate and $9.5g/{\ell}$ of ethanol was produced from the process of pretreatment and SSF. As a result of analyzing the fermentation inhibitors, such as acetic acid, 5-HMF, furfural and total phenolic compounds, as the reaction time increased, the amount of the fermentation inhibitors in the hydrolysate increased. Production of the fermentation inhibitors was more affected by initial concentration of oxalic acid rather than reaction time. $3.39{\sim}5.78g/{\ell}$ of acetic acid was produced by pretreatment with 0.013 g/g of oxalic acid, and the amount of furfural produced by decomposition of xylose was 2~3 times higher than the amount of 5-HMF produced by decomposition of glucose. All the hydrolysates contained more than $5g/{\ell}$ of total phenols considered as the degradation product of lignin. Therefore, by analyzing the amount of fermentable sugars and fermentation inhibitors in the hydrolysate, and producing ethanol from SSF of solid fraction of the pretreated sample, the biomass pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$ can be expected to produce the most ethanol.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.33-40
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• 2013

The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.